Myotonic dystrophy type 1 (DM1) is the most prevalent adult-onset muscular dystrophy affecting 1 in 8,000 individuals. It is characterized by multisystemic symptoms, primarily myopathy. The root ...cause of DM1 is a heterozygous CTG triplet expansion beyond the normal size threshold in the non-coding region of the DM1 protein kinase gene (DMPK). In our study, we generated and characterized three distinct DM1 induced pluripotent stem cell (iPSC) lines with CTG repeat expansions ranging from 900 to 2000 in the DMPK gene. These iPSC lines maintained normal karyotypes, exhibited distinctive colony morphology, robustly expressed pluripotency markers, differentiated into the three primary germ layers, and lacked residual viral vectors.
Myotonic dystrophy Type 1 (DM1) is a severe inherited neuromuscular disease and is the most prevalent form of muscular dystrophy in adults. DM1 involves not only the striated muscles including ...skeletal, and cardiac but also other organs such as the eye, brain and gonads. We have generated and characterized 4 adult heterozygous DM1 iPSC lines carrying between 1300 and 1600 CTG repeat expansion in the DM1 protein kinase gene, and a control from an apparently healthy individual. They all show strong pluripotency markers, differentiation capacity, the absence of residual viral vectors as well as normal karyotypes and colony morphologies.
The generation of control human iPSC lines is important in fundamental research to understand the physiological and physiopathological mechanisms underlying human diseases. We generated and ...characterized two control hiPSC lines from lymphoblastoid cells collected from apparently healthy individuals. These hiPSCs display pluripotency markers, can differentiate into three embryonic germ layers, possess normal karyotypes and colony morphologies, and have no reprogramming viral vectors.
Myotonic dystrophy type 1 (DM1) is a genetic neuromuscular disorder that affects many organs, including the heart. DM1 is caused by a heterozygous CTG triplet expansion exceeding the normal size ...threshold in the non-coding region of the DM1 protein kinase gene (DMPK). We generated and characterized a DM1 iPSC line carrying a 700 CTG repeat expansion as well as a control iPSC line from a healthy individual. The two iPSC lines expressed several pluripotency markers, had the capacity to differentiate into the three primary germ layers, had no residual viral vectors, had normal karyotypes, and had a typical colony morphology.
Myotonic dystrophy type 1 (DM1) is a dominant genetic disease in which the expansion of long CTG trinucleotides in the 3′ UTR of the myotonic dystrophy protein kinase (DMPK) gene results in toxic RNA ...gain-of-function and gene mis-splicing affecting mainly the muscles, the heart, and the brain. The CUG-expanded transcripts are a suitable target for the development of antisense oligonucleotide (ASO) therapies. Various chemical modifications of the sugar-phosphate backbone have been reported to significantly enhance the affinity of ASOs for RNA and their resistance to nucleases, making it possible to reverse DM1-like symptoms following systemic administration in different transgenic mouse models. However, specific tissue delivery remains to be improved to achieve significant clinical outcomes in humans. Several strategies, including ASO conjugation to cell-penetrating peptides, fatty acids, or monoclonal antibodies, have recently been shown to improve potency in muscle and cardiac tissues in mice. Moreover, intrathecal administration of ASOs may be an advantageous complementary administration route to bypass the blood-brain barrier and correct defects of the central nervous system in DM1. This review describes the evolution of the chemical design of antisense oligonucleotides targeting CUG-expanded mRNAs and how recent advances in the field may be game-changing by forwarding laboratory findings into clinical research and treatments for DM1 and other microsatellite diseases.
Dilated cardiomyopathy (DCM) is a prevalent cause of heart failure. We generated induced pluripotent stem cell (iPSC) lines from a DCM patient carrying a mutation in the SCN5A gene, with his healthy ...father serving as a control. Notably, we employed CRISPR-Cas9 to rectify the mutation in the patient’s iPSC line. The resulting iPSC lines expressed pluripotency markers, underwent differentiation into all three embryonic germ layers, maintained a normal karyotype, and lacked reprogramming viral vectors. These iPSC lines serve as a model for delving into the mechanisms of DCM and hold promise for the development of personalized therapeutic approaches.
Congenital myotonic dystrophy (CDM) is an autosomal dominant multisystemic disorder attributed to a large expansion of CTG trinucleotide repeats within the myotonic dystrophy protein kinase (DMPK) ...gene. In this study, we successfully reprogrammed dermal fibroblasts derived from two pediatric CDM patients and two age-matched individuals into induced pluripotent stem cells (iPSCs) using a non-integrating viral vector. The resulting CDM iPSC lines harbored approximately about 2000 CTG in the mutated DMPK allele. These iPSC lines expressed pluripotency markers and exhibited the capacity to differentiate into cells representing all three germinal layers, confirming their reliability as a research tool for investigating CDM and therapeutic strategies.
Congenital myotonic dystrophy (CDM) is a genetic disease caused by an abnormally long CTG repeat expansion in the DMPK gene, which generally increases in size following intergenerational ...transmission. CDM is the rarest and most severe form of myotonic dystrophy type 1, yet an important number of patient-derived cells are needed to study this heterogeneous disease. Therefore, we have reprogrammed lymphoblastoid cells derived from a 3-year-old male with CDM into induced pluripotent stem cells (iPSCs; CBRCULi015-A) featuring 1800 CTG repeats and characterized their pluripotent state. This cell line constitutes an important resource to study CDM and potential treatments in vitro.
Myotonic dystrophy type 1 (DM1), a dominant hereditary muscular dystrophy, is caused by an abnormal expansion of a (CTG)n trinucleotide repeat in the 3′ UTR of the human dystrophia myotonica protein ...kinase (DMPK) gene. As a consequence, mutant transcripts containing expanded CUG repeats are retained in nuclear foci and alter the function of splicing regulatory factors members of the MBNL and CELF families, resulting in alternative splicing misregulation of specific transcripts in affected DM1 tissues. In the present study, we treated DMSXL mice systemically with a 2′-4′-constrained, ethyl-modified (ISIS 486178) antisense oligonucleotide (ASO) targeted to the 3′ UTR of the DMPK gene, which led to a 70% reduction in CUGexp RNA abundance and foci in different skeletal muscles and a 30% reduction in the heart. Furthermore, treatment with ISIS 486178 ASO improved body weight, muscle strength, and muscle histology, whereas no overt toxicity was detected. This is evidence that the reduction of CUGexp RNA improves muscle strength in DM1, suggesting that muscle weakness in DM1 patients may be improved following elimination of toxic RNAs.
Antisense oligonucleotides (ASOs) targeting pathologic RNAs have shown promising therapeutic corrections for many genetic diseases including myotonic dystrophy (DM1). Thus, ASO strategies for DM1 can ...abolish the toxic RNA gain-of-function mechanism caused by nucleus-retained mutant DMPK (DM1 protein kinase) transcripts containing CUG expansions (CUGexps). However, systemic use of ASOs for this muscular disease remains challenging due to poor drug distribution to skeletal muscle. To overcome this limitation, we test an arginine-rich Pip6a cell-penetrating peptide and show that Pip6a-conjugated morpholino phosphorodiamidate oligomer (PMO) dramatically enhanced ASO delivery into striated muscles of DM1 mice following systemic administration in comparison with unconjugated PMO and other ASO strategies. Thus, low-dose treatment with Pip6a-PMO-CAG targeting pathologic expansions is sufficient to reverse both splicing defects and myotonia in DM1 mice and normalizes the overall disease transcriptome. Moreover, treated DM1 patient-derived muscle cells showed that Pip6a-PMO-CAG specifically targets mutant CUGexp-DMPK transcripts to abrogate the detrimental sequestration of MBNL1 splicing factor by nuclear RNA foci and consequently MBNL1 functional loss, responsible for splicing defects and muscle dysfunction. Our results demonstrate that Pip6a-PMO-CAG induces long-lasting correction with high efficacy of DM1-associated phenotypes at both molecular and functional levels, and strongly support the use of advanced peptide conjugates for systemic corrective therapy in DM1.
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